From 23a0d4e8fa6d3a1d7fb819f79bcc0a3739c30ba9 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Tue, 3 Mar 2015 07:34:33 +0100 Subject: [PATCH] efi: Disable interrupts around EFI calls, not in the epilog/prolog calls Tapasweni Pathak reported that we do a kmalloc() in efi_call_phys_prolog() on x86-64 while having interrupts disabled, which is a big no-no, as kmalloc() can sleep. Solve this by removing the irq disabling from the prolog/epilog calls around EFI calls: it's unnecessary, as in this stage we are single threaded in the boot thread, and we don't ever execute this from interrupt contexts. Reported-by: Tapasweni Pathak Signed-off-by: Ingo Molnar Signed-off-by: Matt Fleming --- arch/x86/platform/efi/efi.c | 7 +++++++ arch/x86/platform/efi/efi_32.c | 11 +++-------- arch/x86/platform/efi/efi_64.c | 3 --- 3 files changed, 10 insertions(+), 11 deletions(-) diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index e859d56ce9f8..e7a01e32db95 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -85,12 +85,19 @@ static efi_status_t __init phys_efi_set_virtual_address_map( efi_memory_desc_t *virtual_map) { efi_status_t status; + unsigned long flags; efi_call_phys_prolog(); + + /* Disable interrupts around EFI calls: */ + local_irq_save(flags); status = efi_call_phys(efi_phys.set_virtual_address_map, memory_map_size, descriptor_size, descriptor_version, virtual_map); + local_irq_restore(flags); + efi_call_phys_epilog(); + return status; } diff --git a/arch/x86/platform/efi/efi_32.c b/arch/x86/platform/efi/efi_32.c index 40e7cda52936..abecc6e1dc90 100644 --- a/arch/x86/platform/efi/efi_32.c +++ b/arch/x86/platform/efi/efi_32.c @@ -33,11 +33,10 @@ /* * To make EFI call EFI runtime service in physical addressing mode we need - * prolog/epilog before/after the invocation to disable interrupt, to - * claim EFI runtime service handler exclusively and to duplicate a memory in - * low memory space say 0 - 3G. + * prolog/epilog before/after the invocation to claim the EFI runtime service + * handler exclusively and to duplicate a memory mapping in low memory space, + * say 0 - 3G. */ -static unsigned long efi_rt_eflags; void efi_sync_low_kernel_mappings(void) {} void __init efi_dump_pagetable(void) {} @@ -61,8 +60,6 @@ void __init efi_call_phys_prolog(void) { struct desc_ptr gdt_descr; - local_irq_save(efi_rt_eflags); - load_cr3(initial_page_table); __flush_tlb_all(); @@ -81,8 +78,6 @@ void __init efi_call_phys_epilog(void) load_cr3(swapper_pg_dir); __flush_tlb_all(); - - local_irq_restore(efi_rt_eflags); } void __init efi_runtime_mkexec(void) diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index 17e80d829df0..427eb3540e5f 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -42,7 +42,6 @@ #include static pgd_t *save_pgd __initdata; -static unsigned long efi_flags __initdata; /* * We allocate runtime services regions bottom-up, starting from -4G, i.e. @@ -88,7 +87,6 @@ void __init efi_call_phys_prolog(void) return; early_code_mapping_set_exec(1); - local_irq_save(efi_flags); n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT), PGDIR_SIZE); save_pgd = kmalloc(n_pgds * sizeof(pgd_t), GFP_KERNEL); @@ -116,7 +114,6 @@ void __init efi_call_phys_epilog(void) set_pgd(pgd_offset_k(pgd * PGDIR_SIZE), save_pgd[pgd]); kfree(save_pgd); __flush_tlb_all(); - local_irq_restore(efi_flags); early_code_mapping_set_exec(0); } -- GitLab